It plunged to the ground and exploded into flames, also claiming the life of pilot Peter Barnes, 50, from Berkshire. Twelve other people were injured.

Police have said it was "a miracle" more were not hurt when the helicopter plunged more than 700 feet onto busy streets during the rush hour. Witnesses described hearing a loud bang and a flash of light as the twin-engine aircraft crashed near Wandsworth Road. Video footage and photos flooded on to social media sites revealing chaotic scenes, burning wreckage and vehicles charred by flames.

Stunt pilot Mr Barnes, who has piloted helicopters for movies such as Die Another Day, was alone in the aircraft amid thick cloud when it clipped the structure on top of one of Europe's largest skyscrapers. It came down on land next to the building, with burning wreckage strewn across the road.

Family liaison officers are with the victims' relatives and post-mortem examinations will take place at a later date, Scotland Yard said.

Residents from nearby houses in Lambeth and Wandsworth have not been allowed to return home after debris was scattered over a large area, including on rooftops. In one case of good fortune, it was reported that the crane driver avoided near-certain death because he was late for his shift and had not reached his cabin when it was struck by the helicopter.

In the aftermath of the crash, questions were raised over the safety of aircraft flying over London, especially as the number of high-rise blocks being built increases. But sources said lights fitted to the crane were in place and were checked twice daily - including on Tuesday.

London Fire Brigade station manager Bruce Grain, one of the first firefighters at the scene, said it "was absolute chaos" as residents were evacuated but revealed the fire was put out within 20 minutes. Six fire engines, four fire rescue units, a number of other specialist vehicles and 88 firefighters attended the scene of the crash, a few hundred yards from the future American embassy site. Around 60 police officers also attended the scene.

The eight-seater aircraft is owned by Cornwall-based Castle Air but was leased to another firm RotorMotion, which is based at Redhill Aerodrome. Captain Philip Amadeus, managing director of RotorMotion, an executive helicopter charter business, said the aircraft was on a commercial flight to Elstree. He said: "Our main priority now is for the family of the pilot and we extend our greatest sympathy to the friends and relatives of those who have died and been injured."